A display device of HUD (Head Up Display) type mounted in a vehicle enables a driver to check required information almost without turning his or her eyes from a field of forward view while the driver is driving the vehicle (for example, refer to Patent Literature 1). In recent years, an HUD by which a three-dimensional stereoscopic image can be displayed by adding a depth direction to the display position of information is proposed (for example, refer to Patent Literature 2). In this HUD, by superimposing a display object which is a stereoscopic image on a target object in an actual scene, the parallax between the display object and the target object is eliminated. As a result, a driver can visually recognize information more intuitively. Further, for example, by superimposing a graphic such as an arrow showing the direction toward which the vehicle should make a turn stereoscopically on a road at an intersection, a driver can understand the direction and position of next turning more intuitively compared with a case of displaying a two-dimensional planar image ahead of the driver.